Stator for rotating electric machine

Abstract

A stator includes a hollow cylindrical stator core comprised of a plurality of stator core segments and an outer cylinder fitted on the radially outer surface of the stator core. The stator core has a recess formed in the radially outer surface and the recess has an engaging wall surface that extends in both the axial and radial directions of the stator core. The outer cylinder has a fastening portion for fastening the outer cylinder to the stator core. The fastening portion is formed to be partially surrounded by a plurality of first slits and a second slit. The fastening portion is bent radially inward to have a second slit-side end part thereof received in the recess of the stator core. Further, the second slit-side end part of the fastening portion has a distal end engaging with the engaging wall surface of the recess of the stator core.

What is claimed is: 
     
       1. A stator for a rotating electric machine, the stator comprising:
 a hollow cylindrical stator core comprised of a plurality of stator core segments that are arranged in a circumferential direction of the stator core to adjoin one another in the circumferential direction; 
 a stator coil mounted on the stator core; and 
 an outer cylinder fitted on a radially outer surface of the stator core, 
 wherein 
 the stator core has a recess formed in the radially outer surface thereof, the recess having an engaging wall surface that extends in both an axial direction and a radial direction of the stator core, 
 the outer cylinder has a plurality of first slits and a second slit, all of which radially penetrate the outer cylinder to connect radially outer and inner surfaces of the outer cylinder, 
 the first slits extend in the circumferential direction of the stator core and are spaced from one another in the axial direction of the stator core, 
 the second slit extends in the axial direction of the stator core to connect the first slits, 
 the outer cylinder also has a fastening portion for fastening the outer cylinder to the stator core, the fastening portion being formed to be partially surrounded by the first and second slits, 
 the fastening portion is bent radially inward to have a second slit-side end part thereof received in the recess of the stator core, and 
 the second slit-side end part of the fastening portion has a distal end engaging with the engaging wall surface of the recess of the stator core. 
 
     
     
       2. The stator as set forth in  claim 1 , wherein the fastening portion is located on the stator core so that before the bending of the fastening portion radially inward, the second slit-side end part of the fastening portion protrudes circumferentially toward the opposite side to the recess of the stator core by a predetermined amount from a reference line, the reference line being defined to extend through both a longitudinal axis of the stator core and an intersection between the radially outer surface of the stator core and the engaging wall surface of the recess. 
     
     
       3. The stator as set forth in  claim 1 , wherein on a distal end surface of the second slit-side end part of the fastening portion, there is formed a protrusion that protrudes circumferentially toward the opposite side to the recess of the stator core before the bending of the fastening portion radially inward. 
     
     
       4. The stator as set forth in  claim 1 , wherein a distal end surface of the second slit-side end part of the fastening portion is configured to include at least one of first and second oblique surfaces,
 the first oblique surface faces radially inward and circumferentially toward the opposite side to the recess of the stator core before the bending of the fastening portion radially inward, and 
 the second oblique surface faces radially outward and circumferentially toward the opposite side to the recess of the stator core before the bending of the fastening portion radially inward. 
 
     
     
       5. The stator as set forth in  claim 1 , wherein the fastening portion of the outer cylinder is a first fastening portion and the engaging wall surface is a first engaging wall surface that engages with the distal end of the second slit-side end part of the first fastening portion,
 the outer cylinder also has a second fastening portion for fastening the outer cylinder to the stator core, the second fastening portion being formed in a same manner as the first fastening portion to have a second slit-side end part with a distal end, the distal ends of the second slit-side end parts of the first and second fastening portions facing respectively toward opposite circumferential sides, and 
 in the stator core, there is also formed a second engaging wall surface in a same manner as the first engaging wall surface, the second engaging wall surface engaging with the distal end of the second slit-side end part of the second fastening portion of the outer cylinder. 
 
     
     
       6. The stator as set forth in  claim 5 , wherein both the first and second engaging wall surfaces are formed in a same one of the stator core segments. 
     
     
       7. The stator as set forth in  claim 5 , wherein the first and second engaging wall surfaces are formed respectively in two different ones of the stator core segments. 
     
     
       8. The stator as set forth in  claim 1 , wherein the distal end of the second slit-side end part of the fastening portion of the outer cylinder is kept in pressed contact with the engaging wall surface of the recess of the stator core by springback of the second slit-side end part. 
     
     
       9. The stator as set forth in  claim 1 , wherein the engaging wall surface of the recess of the stator core is positioned closer to the distal end of the second slit-side end part of the fastening portion of the outer cylinder than to a bending start point of the fastening portion.